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Figure 1. Map of Norway showing the positions sample collection areas. Numbers correspond to numbers given in Table 1.
Figure 2. Box plot of the measured equatorial width (E) of pollen. The box encloses the middle half of the data of the second and third quartiles, the thick horizontal line is the median, and the vertical lines show the range of data values in the first and fourth quartiles. Extreme outliers are shown as open circles. Colors of boxes refer to ploidy level (from Table 2). The inset box shows a plot of the correlation between E and ploidy level. The correlation is 0.45.
Figure 3. Box plot of the measured polar length (P) of pollen. The box encloses the middle half of the data of the second and third quartiles, the thick horizontal line is the median, and the vertical lines show the range of data values in the first and fourth quartiles. Extreme outliers are shown as open circles. Colors of boxes refer to ploidy level (from Table 2).
Figure 4. Box plot of the measured of the P/E ratio. The box encloses the middle half of the data of the second and third quartiles, the thick horizontal line is the median, and the vertical lines show the range of data values in the first and fourth quartiles. Extreme outliers are shown as open circles. Colors of boxes refer to ploidy level (from Table 2) and vertical dotted lines mark different shapes of pollen following Erdtman (1952).
Figure 5. Scanning electron microscopy (SEM) images pollen from each specimen analysed in (1) polar view, (2) equatorial view, and (3) close-up of pollen grain exine ornamentation. The scale bars are 2 µm.
Figure 6. The first two axes resulting from the Principal Component Analysis (PCA) of pollen measurements (P and E) and the calculated ratio (P/E) from this study. The ploidy levels (from Table 2) are referred to in the different colors.
Figure 7. The first two resulting axes from the Principal Component Analysis (PCA) of all pollen characters (as given in Table 3). Different genera are marked in colors.
Figure 8.  The calculated P/E ratio from measurements in this study compared with several other studies. Colors of bars refer to the data source.
Table 1. Species included in this study with origin, herbarium, and collection numbers, date of collection, and endemism status. Numbers in brackets are referring to Figure 1.
Table 2. DNA content with measured or given polyploidy levels. * are taken from (Kurtto et al., 2018).
Table 3. Morphological characteristics of the pollen surface interpreted from the SEM pictures in Figure 5.